It is much simpler than hiring an employee or even a contractor in US - through B2B contract. Basically, you buy services from them. They send invoices e.g. at

It is much simpler than hiring an employee or even a contractor in US - through B2B contract. Basically, you buy services from them. They send invoices e.g. at the end of the month, you do regular bank transfers (or any other legit way of money transfer). Since the contractors are outside US, you don't even have a burden of proof that they are not employees but real contractors.